GOUT UPDATE AHMED YEHIA 2024, case based approach with application of the lat...
Aquasomes
1. Submitted to:
Dr. B. Wilson
Head of the Department,
Department of Pharmaceutics,
College of Pharmaceutical Sciences, DSU
Banglore.
Presented by:
Arpitha B M
M Pharm (II SEM),
Department of Pharmaceutics,
COPS, DSU
Banglore .
AQUASOMES
3. Introduction
• It was first developed by NIR KOSSOVSKY
• Aquasomes are spherical in shape with 60–300 nm (less than 1000nm)
particles size.
• These are nanoparticulate carrier systems and are three layered self
assembled structures.
• These structures are self assembled by non covalent and ionic bonds.
• The delivery system has been successfully utilized for the delivery of
insulin, hemoglobin, and enzymes like serratiopeptidase etc
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Aquasomes
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4. Definition
• Aquasomes are nanoparticulate carrier system but instead of
being simple nanoparticle these are three layered self
assembled structures, comprised of a solid phase
nanocrystalline core coated with oligomeric
• film on which biochemically active molecules are adsorbed
with or without modification. The solid core provides
the structural stability, while the carbohydrate
coating protects against dehydration and stabilizes
the biochemically active molecules.
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5. • Aquasomes are like “bodies of water" and thei water like properties
protect and preserve fragile biological molecules, and this property of
maintaining conformational integrity.
• High degree of surface exposure is exploited in targeting of bioactive
molecules like peptide and protein hormones, enzymes, antigens and
genes to specific sites.
• These three layered structures are self-assembled by non covalent and
ionic bonds. These carbohydrate stabilize nanoparticles of ceramic are
known as “aquasomes”.
• The pharmacologically active molecule incorporated by co-
polymerization, diffusion or adsorption to carbohydrate surface of pre
formed nanoparticles.
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6. • Aquasomes discovery comprises a principle from microbiology, food
chemistry, biophysics and many discoveries including solid phase
synthesis, supramolecular chemistry, molecular shape change and self
assembly.
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7. Advantages
• The main objective is to protect bio-actives
• Increases therapeutic efficacy of pharmaceutically active agents.
• Avoid multiple-injection schedule
• Offer favourable environment for proteins
• Used for various imaging tests
• Novel carrier for enzymes such as DNAses and pigment/dyes.
• Act as a vaccine delivery system
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8. Composition of Aquasomes
I- Core material:
• Ceramic and polymers are most widely used core materials. Polymers
such as albumin, gelatin or acrylate are used.
• Ceramic such as diamond particles, brushite (calcium phosphate) and
tin oxide are used.
II- Coating material:
• Coating materials commonly used are cellobiose, pyridoxal 5
phosphate, sucrose, trehalose, chitosan, citrate etc. Carbohydrate plays
important role act as natural stabilizer, its stabilization efficiency has
been reported.
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9. • Beginning with preformed carbon ceramic nanoparticle and self
assembled calcium phosphate dihydrate particles (colloidal
precipitation) to which glassy carbohydrate are then allowed to adsorb
as a nanometer thick surface coating a molecular carrier is formed.
III- Bioactive:
• They have the property of interacting with film via non covalent and
ionic interactions
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10. Role of disaccharides:
• The hydroxyl group on carbohydrate interacts with polar and charged
groups on the proteins, in a similar manner to water molecules alone
and preserve the aqueous structure of proteins on dehydration.
• Disaccharides such as trehalose are reported to have stress tolerance in
fungi, bacteria, insects, yeast and some plants.
• Trehalose works by protecting proteins and membranes within plant
cell during the desiccation process and thereby preserves cell
structures, inherent flavors, colors and textures.
• These disaccharides rich in hydroxyl group and help to replace the
water around polar residues in proteins, thereby maintaining their
integrity in the absence of water.
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11. • When Ca-transporting microsomes were lyophilized without
stabilizing sugar, the rehydrated vesicles shows greatly reduced Ca-
uptake and uncoupling of ATPase activity.
• Vesicles lyophilized in presence of as little as 0.3 g. Of trehalose per g.
membrane upon rehydration are morphologically distinguishable from
freshly prepared vesicles.
• Among three layers of aquasomes, carbohydrate fulfills the objective
of aquasomes. The hydroxyl groups on oligomer interact with polar
and charged groups of proteins, in a same way as with water thus
preserve the aqueous structure of proteins on dehydration.
• The most commonly used carbohydrates are cellobiose, pyridoxal-5-
phosphate, trehalose, sucrose, citrates etc.
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Aquasomes
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12. Properties of aquasomes
• Aquasome possess large size and active surface hence can be
efficiently loaded with substantial amounts of agents through ionic,
non co-valent bonds, van der waals forces and entropic forces.
• As solid particles dispersed in aqueous environment, exhibit physical
properties of colloids.
• Aquasome mechanism of action is controlled by their surface
chemistry.
• Aquasomes deliver contents through combination of specific targeting,
molecular shielding, and slow and sustained release process.
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13. • Aquasomes water like properties provides a platform for preserving
the conformational integrity and bio chemical stability of bio-actives.
• Aquasomes due to their size and structural stability, avoid clearance by
reticuloendothelial system or degradation by other environmental
challenges.
• Aquasome is colloidal range biodegradable nanoparticles, so that they
will be more concentrated in liver and muscles.
• Aquasomes are mainly characterized for structural analysis, particle
size, and morphology.
• These are evaluated by X ray powder diffractometry, transmission
electron microscopy, and scanning electron microscopy.
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14. Method of preparation of aquasomes
The general procedure consists of
1. Formation of an inorganic core,
2. Coating of the core with polyhydroxy oligomer, and
3. finally loading of the drug of choice to this assembly
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15. I- Formation of an inorganic core:
• It involves the fabrication of a ceramic core, and the procedure depends upon the
materials selected.
• The two most commonly used ceramic cores are calcium phosphate and diamond.
a) Synthesis of nanocrystalline tin oxide core ceramic. It can be
synthesized by direct current reactive magnetron sputtering.
The ultrafine particles formed in the gas phase are then collected
on copper tubes cooled to 770 K with flowing nitrogen.
b) Self assembled nanocrystalline brushite (calcium phosphate
dihydrate) .These can be prepared by colloidal precipitation
ansonication by reacting solution of disodium hydrogen phosphate and
calcium chloride.
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16. c) Nanocrystalline carbon ceramic, diamond particles.
• These can also be used for the core synthesis after ultra
cleansing and sonication.
• The common feature of various cores is that they are
crystalline and that when they are introduced into the
synthetic processes, they measures between 50-150 nm
and exhibit extremely clean and therefore reactive
species.
• Ceramic materials, being structurally highly regular, are
most widely used for core fabrication. The high degree of
order in crystalline ceramics ensures only a limited effect
on the nature of atoms below the surface layer when any
surface modification is being done, thus preserving the
bulk properties of ceramics.
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17. • This high degree of order also offers a high level of surface energy that
favors the binding of pohyhydroxyl oligomeric surface film. The
precipitated cores are centrifuged and then washed with enough
distilled water to remove sodium chloride formed during the reaction.
The precipitates are resuspended in distilled water and passed through
a fine membrane filter to collect the particles of desired size. The
equation for the reaction is as follows:
• 2 Na2HPO4 + 3 CaCl2 + H2O → Ca3(PO4)2 + 4 NaCl + 2 H2 + Cl2
+ (O).
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18. II- Coating of the core with polyhydroxy oligomer:
• In the second step, ceramic cores are coated with carbohydrate (polyhydroxyl
oligomer). The coating is carried out by addition of carbohydrate into an aqueous
dispersion of the cores under sonication. These are then subjected to lyophilization
to promote an irreversible adsorption of carbohydrate onto the ceramic surface.
The unadsorbed carbohydrate is removed by centrifugation. The commonly used
coating materials are cellobiose, citrate, pyridoxal-5- phosphate, trehalose and
sucrose.
III- Loading of the drug of choice to this assembly:
• The final stage involves the loading of drug to the coated particles by adsorption.
For that, a solution of known concentration of drug is prepared in suitable pH
buffer, and coated particles are dispersed into it. The dispersion is then either kept
overnight at low temperature for drug loading or lyophilized after some time so as
to obtain the drug-loaded formulation (i.e., aquasomes). The preparation thus
obtained is then characterized using various techniques.
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19. Characterization of aquasomes
• Aquasomes are characterized chiefly for their structural and
morphological properties, particle size distribution, and drugloading
capacity.
Characterization of ceramic core:
• Size distribution: For morphological characterization and size
distribution analysis, scanning electron microscopy (SEM) and
transmission electron microscopy (TEM) are generally used. Core,
coated core, as well as drug-loaded aquasomes are analyzed by these
techniques. Mean particle size and zeta potential of the particles can
also be determined by using photon correlation spectroscopy.
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20. • Structural analysis: FT-IR spectroscopy can be used for structural
analysis. Using the potassium bromide sample disk method, the core
as well as the coated core can be analyzed by recording their IR
spectra in the wave number range 4000–400 cm–1 ; the characteristic
peaks observed are then matched with reference peaks. Identification
of sugar and drug loaded over the ceramic core can also be confirmed
by FT-IR analysis of the sample.
• Crystallinity: The prepared ceramic core can be analyzed for its
crystalline or amorphous behavior using X-ray diffraction. In this
technique, the X-ray diffraction pattern of the sample is compared
with the standard diffractogram, based on which the interpretations are
made.
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21. Characterization of coated core:
• Carbohydrate coating Coating of sugar over the ceramic core can be
confirmed by concanavalin A–induced aggregation method
(determines the amount of sugar coated over core) or by anthrone
method (determines the residual sugar unbound or residual sugar
remaining after coating).
• Glass transition temperature DSC can be used to analyze the effect of
carbohydrate on the drug loaded to aquasomes. DSC studies have been
extensively used to study glass transition temperature of carbohydrates
and proteins. The transition from glass to rubber state can be measured
using a DSC analyzer as a change in temperature upon melting of
glass.
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22. Characterization of drug-loaded aquasomes
• Drug payload: The drug loading can be determined by incubating the
basic aquasome formulation (i.e., without drug) in a known
concentration of the drug solution for 24 hours at 4°C. The supernatant
is then separated by high-speed centrifugation for 1 hour at low
temperature in a refrigerated centrifuge. The drug remaining in the
supernatant liquid after loading can be estimated by any suitable
method of analysis.
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23. • In vitro drug release studies :The in vitro release kinetics of the
loaded drug is determined to study the release pattern of drug from the
aquasomes by incubating a known quantity of drug-loaded aquasomes
in a buffer of suitable pH at 37°C with continuous stirring. Samples
are withdrawn periodically and centrifuged at high speed for certain
lengths of time. Equal volumes of medium must be replaced after each
withdrawal. The supernatants are then analyzed for the amount of drug
released by any suitable method.
• In-process stability studies: SDS-PAGE (sodium dodecyl sulphate
polyacrylamide gel electrophoresis) can be performed to determine the
stability and integrity of protein during the formulation of the
aquasomes.
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24. Applications of aquasomes
Insulin delivery:
The prolonged activity was attributed to slow release of drug from the
carrier and structural integrity of the peptide.
The utility of nanocarriers for effective delivery of insulin was also
proved by Paul and Sharma.
They prepared porous hydroxyapatite nanoparticles entrapped in
alginate matrix containing insulin for oral administration.
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25. Oral delivery of acid labile enzyme:
These aquasomes were found to be protecting the structural integrity of
enzymes so as to obtain a better therapeutic effect.
As oxygen carrier:
The oxygencarrying capacity of aquasome formulation was found to be
similar to that of fresh blood.
Antigen delivery:
The use of ceramic core–based nanodecoy systems was proposed as an
adjuvant and delivery vehicle for hepatitis B vaccine for effective
immunization.
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26. For delivery of gene:
Aquasomes can be studied for the delivery of genes. It illustrates the
attractive delivery system loaded with genetic material.
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27. For delivery of enzymes:
Aquasomes also used for delivery of enzymes like DNAase and
pigment/dyes because enzymes activity fluctuates with molecular
conformation and cosmetic properties of pigment are sensitive to
molecular conformation
DNAase a therapeutic enzyme used in the treatment of cystic fibrosis.
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